First Law of Thermodynamics

Question 1

Define specific heat capacity.

Answer 1

The specific heat capacity of a substance is the thermal energy per unit mass to raise the temperature of a substance by one degree kelvin.

Question 2

Define specific latent heat of fusion and vaporization.

Answer 2

The specific latent heat of fusion is defined as the amount of thermal energy required per unit mass to change a substnce from solid phase to liquid phase at constant temperature.

The specific latent heat of vaporization is defined as the amount of thermal energy required per unit mass to change a substance from liquid phase to vapor phase at a contant temperature.

Question 3

What is the First Law of Thermodynamics?

Answer 3

The FIrst Law of Thermodynamics states that in a closed system, the increase in internal energy is equal to the heat supplied to the system and the work done on the system.
ΔU = Q + W
If Q is positive, heat is supplied. If Q is negative, heat is released.
If W is positive, work is done on system (compression).
If W is negative, work is done by system (expansion).

Question 4

Thermodynamic Processes

Answer 4

Isothermal: no change in temperature
Isovolumetric/isochoric: no change in volume
Isobaric: no change in pressure
Adiabatic: no heat gain or loss throughout
Cylic: no net change of internal energy